In 109 BCE,
Emperor Wu launched a Han military campaign into Gojoseon. Yang Pu (楊浦) and Xun Zhi (尋知) respectively—set out from the Han empire to invade Gojoseon. Yang Pu's army of 50,000 sailed from Qi (present-day
Shandong Province) across the
Bohai Sea towards Gojoseon, while Xun Zhi marched by land through
Liaodong and headed towards
Wanggeom, the capital of Gojoseon. One of Yang's commanders by the name of Duo took command of a large number of troops and lead them ahead as a vanguard force. He suffered a disastrous defeat. As a result, Yang Pu had only 7,000 men with him when they reached the capital of Gojoseon,
Wanggeom-seong. Seeing how small the enemy army was, King Ugeo marched out, defeating and routing Yang Pu's army. Yang Pu spent the next ten days rounding up the remnants of his army, which had fled into the nearby mountains. Meanwhile, Xun Zhi failed to break Gojoseon's army west of the
Yalu River. When Emperor Wu received news of these defeats, he wished to reestablish peaceful relations between Han and Gojoseon. King Ugeo agreed, and to make amends, he sent his son and a gift of 5,000 horses to the Han court. When the prince and his escort of 10,000 soldiers reached the Yalu River, Xun Zhi reasoned that they should lay down arms. The prince suspected that Xun Zhi was planning on murdering him and so went back to Wanggeom-seong, resuming the war. Xun Zhi attacked the Gojoseon army again and succeeded in defeating it this time. Xun Zhi and Yang Pu converged on Wanggeom-seong and laid siege to it, but the city was well guarded, and after several months it had still not fallen. After a sudden attack by Xun Zhi, the high minister of Gojoseon secretly sent envoys to discuss terms of surrender with Yang Pu, however no final agreement was reached. Xun Zhi wished to make an all out attack on the city but Yang Pu favored continued negotiations, therefore relations between the two generals began to strain. When Emperor Wu sent the governor of
Jinan, Gongsun Sui, to straighten things out, Xun Zhi told him that Yang Pu was delaying the defeat of Gojoseon. Gongsun Sui agreed with him and used his imperial credentials to summon Yang Pu to Xun Zhi's camp. Once there, they arrested Yang Pu and took command of his army. Emperor Wu was displeased by this turn of events and sent orders for Gongsun Sui to be executed. With both armies under his command, Xun Zhi made preparations for a final attack on Wanggeom. Officials such as
No In,
Han Eum,
Sam of Gojoseon,
Wang Gyeop insisted on surrendering to the Han, but King Ugeo disagreed. In April of 108 BCE, Wang Gyeop, No In, Han Eum, and Sam surrendered to the Han. Sam later sent assassins into Wanggeom-seong and killed King Ugeo. Wanggeom-seong still struggled on under the leadership of Minister Seong Gi (成基) but Seong Gi was also assassinated. Eventually, the people of Wanggeom-seong were convinced to surrender by the sons of King Ugeo and No In. In 108 BCE, all of Gojoseon had fallen and was conquered by the Han. ==Aftermath==